Understanding Ovarian Cysts

Ovaries are the two small organs - the size of large strawberries - on both sides of the uterus. They are responsible for producing eggs each menstrual cycle and manufacturing the female sex hormones - estrogen and progesterone - which regulate the growth of the uterine lining and support a pregnancy as well as maintain the mental, cardiac and sexual health of a woman.

What are ovarian cysts?

Sometimes, ovarian cysts may develop within the ovaries. An ovarian cyst is any collection of fluid, surrounded by a wall. Most ovarian cysts are functional in nature and harmless (benign). Ovarian cysts affect women of all ages but they are most common in those their 20s to 40s, and can range widely in size from being pea-sized to melon-sized.

There are basically two types of cysts and one has to be certain which part of the menstrual cycle a woman is in to help make the diagnosis correctly. At the start of every cycle, several small follicles approximately 3-5mm start to grow but eventually only one follicle will grow to be the dominant follicle of 17-22mm which will release the egg during ovulation.

Functional cysts are the most common. They form during ovulation and this happens either when the egg is not released or when the sac - follicle - in which the egg forms does not dissolve after the egg is released.

Non functional cysts include:

Endometriosis: This is where the lining of the uterus grows in other areas of the body, including the ovaries. Hence when menstruation occurs, these abnormal areas also menstruate and the blood is collected as blood filled sacs within the ovary. They can cause a lot of pain and potentially adversely affect fertility.

Serious or mucinous cystadenomas:These cysts form out of cells on the surface of the ovary. They are filled with clear fluid for the serous type and sticky mucus for the mucinous variety.

Dermoid cysts: This type of cyst is formed from cells destined originally to form a baby and hence these cysts contain skin cells, fat, hair, and teeth.

Polycystic ovaries: In Polycystic Ovarian Syndrome (PCOS), the follicles in which the eggs normally mature fail to develop and get arrested at various stages, The typical look is that of a “pearl bracelet” on ultrasound. It is actually a misnomer to call them “cysts” as they are really follicles!

Ovarian tumours

Tumours can form in the ovaries, just as they can form in other parts of the body. These tumours can form on any of the three cell lines in the ovaries, that is, the germ cells, the stromal cells or the surface epithelial cells. Ovarian cancer tends to occur during the post menopausal years and unfortunately tends to present as a late disease as there are no specific symptoms.

Risk factors for this type of cancer are menopause, smoking, obesity, not having children, and not breastfeeding. The excessive use of fertility drugs or hormone replacement therapy, and a family or personal history of ovarian, breast, or colorectal cancer (having the BRCA gene) may also increase one’s risk of getting the disease.

On the contrary, a history of having used oral contraceptive pills will reduce the risk of ovarian cancer.

How to diagnose ovarian cysts / tumours Most ovarian cysts do not present with any symptoms especially when they are smaller than 5cm in diameter. When they become larger, they present with a variety of symptoms.

Typically, there is abdominal distension and at times, pelvic pain. The pain could be dull and achy or sudden, severe and sharp in nature. There may be menstrual disturbances and breast complaints when the hormonal cycle is disrupted. Infertility is a common result as well.

As the presence of cysts puts pressure on the bladder and bowels, there would usually be complaints of frequent urination or constipation.

An abdominal examination could reveal an abnormal mass arising from the pelvis into the abdomen. A pelvic or transabdominal ultrasound scan can then be used to determine the nature and origin of the mass. Should there be features suggesting malignancy, a CT Scan of the mass and the surrounding structures is needed to give doctors a clearer picture of what exactly is happening in the patient’s body.

Blood tests for serum CA 125 and other tumour markers such as AFP or CEA may shed light on the type of cyst present.

Treatment

Taking oral contraceptive pills or undergoing a simple hormonal treatment usually makes functional cysts disappear. Managing non functional cysts would depend on the type of cyst, the age of the patient and the desire for future fertility. A simple cyst is often more likely to be benign than a complex cyst, that is, those with thick walls and compartments or solid areas within.

A final word of caution

It is impossible to be entirely 100 per cent sure that the cysts are benign but the use of a well-timed pelvic ultrasound and blood tests will give one more certainty prior to surgery and determine if surgery is really needed or not.

Dr Ann Tan is the first Singaporean to hold the Diploma of Fetal Medicine from the Fetal Medicine Foundation. She presently serves on the Women’s Health Advisory Committee at the Health Promotion Board. Dr Ann Tan was a Public Service Commission Scholar, and has won several prestigious awards in her field of specialization.

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